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Molybdenum Resources
Molybdenum (Mo) is a silvery-gray group 6 transition metal with atomic number 42. The name is derived from the Greek word molybdos ''meaning iron, as its ore were mistaken for lead ores. Its physical properties are exceptional. Namely, it boasts one of the lowest coefficient of thermal expansion as well as the sixth highest melting point among the naturally occurring elements (2896 K). It does not exist naturally as a free metal but rather occupies oxidation states from -2 to +7. Additionally Mo takes a body centered cubic lattice structure. Origins Molybdenum ranks as the 54th most abundant element in the Earth's crust and the 25th most abundant in the Earth's oceans, having an average concentration of 10 ppb. 10ppb. Throughout the universe Molydenum is the 42nd most abundant element. Molydenum is most often found in water insoluble sulfer combined ores, as well as in certain minerals such as wulfenite (PbMoO4) and powelite (CaMoO4). However, the main source of commercial Molybednum is molybdenite (MoS2). The first molybdemum mine was oppened in Norway in 1885, named the Knaben mine. Currently, large molybdenum mines can be found in Colorado (Henderson and Climax mines) and in British Columbia. Molybdenum is also extracted as a by-product of copper mining.copper mining. The Bringham Canyon Mine in Utah and the Chuquicatama mine in Chile are two significant copper mines in which molybdenum is extracted. In total there is an estimated 10 million tons of molybdenum reserves: the majority being concentrated in China (4.3mt), the U.S. (2.1mt), and Chile (1.2 mt). 93% of molybdemum production is from China and North and South American countries with the remaining production divided between the rest of Asia and Europe.Europe. Molybdenum Production Molybdenum metal is created through the practice of molybdenite processing. To begin the mined molybdenite must be oxidized into Molybdenum (VI) oxide. This is accomplished at 700 degrees Celsius according to the following reaction 2 MoS2 + 7 O2 → 2 MoO3 + 4 SO2 The ore is then heated to 1,100 degrees Celsius in order to sublimate the oxide, or it is leached with ammonia which will facilitate the formation of molybdenates MoO3 + 2 NH4OH → (NH4)2(MoO4) + H2O This product is precipitated from solution through the addition of hydrogen sulfide. Pure molybdenum can then be produced by reducing the oxide with hydrogen and molydenum for steel production is reduced by a "aluminothermic reaction" in which iron is added to produce ferromolybdenum. Usage The main applications of molybdenum are in steel alloys, where it gives great strength and heat resistance, most notably to M-series high-speed tool steels. Molybdenum also known for its high corrosion resistance and its easiness to join with another metals. Pure molybdenum is much less common, but is used in situations where a part must withstand great stress for extended periods at high temperature, for example in pressure vessels. The Elemental molybdenum also used to detect NO, NO2, NOx in pollution controls as it will react with these gasses and forming NO which could be detected easily. From resisting movement to encouraging it: molybdenum disulfide is an excellent ultra-high-pressure lubricant. Either as a dry powder or mixed with oil or grease, it is able to withstand crushing pressures and fearsome temperatures without seizing up. In the form of powder, molybdenum also used as fertilizer in soil for plants. Molybdenum leads to its neighbor, technetium (43), in a very direct way. The technetium-99m isotopes is needed for medical imaging purposes, it has to be created on the spot due to its half-life is short. This could be done by decaying molybdenum-99 into technetium-99m, continually replenishing the supply within the device. In biochemistry, some bacteria used molybdenum for nitrogen fixation around their active site in certain enzymes. Some molybdenum is present in human tooth enamel as to protect the tooth from decaying. Global Impact The price of Molybdenum is currently about $24,500 per tonne.4 For reference, this is about 10 times the price of aluminum. There are currently about 10 million tonnes of known Molybdenum reserves, and about 250,000 tonnes were produced in 2011.3 Approximately 30% of post-consumer Mo is functionally recycled, which in comparison to other ferrous metals, is fairly low.5 Based on these numbers, with no predicted growth in demand, the current Mo reserves will last less than 60 years. With the increasing demand for Molybdenum due to increasing industrialization and increase in steel consumption, this supply will likely dwindle even faster. The BRIC countries (Brazil, Russia, India, and China) which are experiencing rapidly growing economic development will likely have increasing demands for molybdenum. China, with its particularly large supply of molybdenum and rapid industrialization, is expected to steadily increase demand for molybdenum.6 It is therefore important that the industry look for better recycling methods. The amount of a metal that is recycled depends on two main factors. First is the price of the material; the more expensive the metal the more efforts are made to recycle it. Second is the difficulty of recycling the metal, which is primarily related to the application of the metal. For example, a metal that is used in low concentrations in an electronic component will be very difficult to recover. A combination of these two factors is responsible for the low recycling rate in Molybdenum. Most recycling of molybdenum alloys does not recover pure molybdenum, but is simply used to create new alloys, and thus the demand for recycling of molybdenum will be tied to the demand for alloys of the same type. Currently, the low price of molybdenum means that scrap metal is not sought for its molybdenum content and the current recycling rate is expected to remain constant. Health/Environmental Concerns Molydenum is an essential part of the human diet, and in the United States the commonly observed intake levels are well below the levels that could cause injury. However, molydenum is used in some forms of fertilizer, and these traces can cause health problems for humans and livestock alike if not controlled. A study in India showed a connection between high intakes of molydenum containing cereals and lower limb osteoperosis. In addition, a study in the former Soviet Union showed a connection between high molydenum intake and gout like symptoms. 7 Thus, it is important to control the amount of molydenum remaining in fertilizers and in food products. References 1 Considine, Glenn D., ed. (2005). "Molybdenum". ''Van Nostrand's Encyclopedia of Chemistry. New York: Wiley-Interscience. pp. 1038–1040. 2 Lide, David R., ed. (1994). "Molybdenum". CRC Handbook of Chemistry and Physics 4. Chemical Rubber Publishing Company. p. 18. ISBN 0-8493-0474-1. 3"Molybdenum Statistics and Information". U.S. Geological Survey. 2007-05-10. 4 http://www.lme.com/en-gb/metals/minor-metals/molybdenum/ 5 Blossom, J.W. 2004, Molydenum recycling in the United States in 1998, USGS Circular 1196-L 6 http://www.prnewswire.com/news-releases/china-to-continue-driving-molybdenum-demand-82778377.html 7 http://www.who.int/water_sanitation_health/dwq/chemicals/molybdenum.pdf